The present invention concerns a visualization device for alignment and positioning with respect to micro-mechanical and micro-optical devices, including micro-electronic (chips), and opto-electronic devices (laser diodes, photo-diodes), or others by component reversal method (alignment of two opposite surfaces). The assembly process is schematically represented in FIGS. 1a and 1b. 
With respect to FIG. 1a, the examined component transfer method consists of placing in accurate fashion, one or several components 1 on a substrate 2. In general, component 1 and the substrate 2 are not transparent. In order to assure precise placement, alignment marks 3 and 4 can respectively be traced on the lower surface of component 1 and the upper surface of the substrate 2. Final assembly of the device can be realized by means of gluing, welding or natural adhesion thanks to the possible presence of welding contacts 5 and 6 or glue, which are respectively present on component 1 and/or the substrate 2. Any other assembly method can also be envisioned. This final assembly constitutes a new hybrid componentxe2x80x94FIG. 1b. 
When the assembly involves small components (size on the order from 0.2 mm to 5 mm) for which high precision in placement is required (on the order from 0.5 xcexcm to several xcexcm) a number of different methods are usually utilized.
FIG. 2a and FIG. 2b illustrate a method which consists of utilizing a dual sighting system comprising two microscope lenses 7 and 8, one sighting the lower surface of component 1, the other sighting the upper surface of substrate 2. These microscopes permit visualizing the alignment designs 3 and 4 and allow for correction of placement defects.
Following correction, a movement of retraction 9 is applied to the sighting system, since a displacement program is applied to the component 1 through the intermediary of a mechanical device 11 in order to place same on the substrate 2.
This method poses the following technical problems:
Utilization of two microscopic sighting systems requiring precisely the same characteristics (pairing).
Need to retract the microscopes before placement of component.
Significant placement distance of component, detrimental to large production output.
FIG. 3a and FIG. 3b illustrate a variation of the preceding method, utilizing two fixed microscopes 7 and 8 and applying two displacements 10 and 12 to the component
This method poses the following technical problems:
Utilization of two microscopic sighting systems needing precisely the same characteristics (pairing).
Two significant placement distances of the component, detrimental to large production output.
Need for horizontal displacement 10 with absolute high precision.
FIG. 4a and FIG. 4b illustrate a method utilizing a single microscopic sighting system 13 and a beam separator cube 14 permitting superposing the images of the component 1 and the substrate 2 at time of alignment. Following alignment, a retraction movement 15 of the separator cube 14 is performed in order to position the component 1 on the substrate 2.
This method poses the following technical problems:
The final position of the component is sensitive to the thickness of the component (a very thin component will result in quite significant tilting and a very thick component will result in very weak tilting).
Need to retract the prism before placement of component.
Significant sighting distance, generally incompatible with utilization of high resolution and strong magnification microscopes.
Sighting through heavy glass, generally detrimental with the use of strong magnification microscopes.
FIG. 5a and FIG. 5b illustrate a method utilizing a single microscopic sighting system 13 and a semi-reflecting plate 17 permitting superposing the images of the component 1 and the substrate 2 at time of alignment. After alignment, a displacement program 10 is applied to the component 1 through the intermediary of a mechanical device 11 in order to place same on the substrate 2.
This method poses the following technical problems:
The final position of the component is sensitive to the thickness of the component, the system presenting a defect in parallax (absence of parallelism between the sighting axis 18 and the deposit axis 10).
Significant sighting distance, generally incompatible with high resolution and strong magnification microscopes.
Sighting of substrate 2 through a semi-reflecting glass plate 17 inclined in relation to the median sighting axis 18. Said configuration introduces optical aberrations such as coma and astigmatism, which reduces the resolution and enlargement capacities of the sighting system.
FIG. 6a and FIG. 6b illustrate a method which is applicable when the component 1 is transparent over the length of the light wave utilized by the microscopic sighting system 13. Sighting takes place through the transparent support 11 of the component 1. When in alignment phase, the component 1 and the substrate 2 are separated by sufficient distance (d) so that the alignment movements can take place without contacts 5 and 6 touching each other. Following alignment, a transfer program 10 is applied to the component 1 through the intermediary of a mechanical device 11 in order to place same on the substrate 2.
This method poses the following technical problems:
Component 1 must be transparent and its two surfaces must be perfectly polished in order to permit formation of images of the substrate 2 and the component 1.
The component generally being semi-conductive, it is then necessary to resort to infra-red sighting systems.
The required separation distance (d) at time of alignment prevents perfect adjustment of the sighting system, simultaneously, as to the component 1 and the substrate 2.
The metallizations which are present on the bottom surface of the component 1 act as a screen and do not permit the visualization of the totality of the surface of the substrate 2.
It is impossible to differently illuminate the component 1 and the substrate 2.
The present invention provides a new and improved method and apparatus that overcomes the above referenced problems and others.
In accordance with one aspect of the present invention, an aligning device for microsystems is provided. The device includes a sighting system, a semi-reflective plate and a mechanical device for positioning a component. The reflective plate has a normal that merges with an optical axis of the sighting system.
One advantage of the present invention resides in utilization of a single microscopic sighting system for alignment of two components.
Another advantage resides in forming an enlarged image exactly united with the lower surface of component 1.
Another advantage resides in the placement of component 1 on substrate 2 without having to displace the microscopic sighting system 22.
Another advantage resides in minimizing the distance between the component 1 and the substrate 2 at time of alignment phase of the two components.
Another advantage resides in utilizing sighting devices 22 with high numerical apertures, compatible with high resolutions and strong magnifications, resulting in providing assurance of great precision in placement of the component 1 in relation to the substrate 2.
Another advantage resides in visualization of the lower surface of the component 1 and of the upper surface of the substrate 2 without parallax effect.
Another advantage resides in alignment of non-transparent components.
Another advantage resides in utilization of a relative alignment principle which does not require absolute displacement precision 10 of the maintenance device 11 of the component 1 when the latter is placed on the substrate 2.
Still further benefits and advantages of the present invention will become apparent to those skilled in the art upon a reading and understanding of the preferred embodiments.